The cloud computing mainly includes increase, usage and delivery modes based on Internet-related services. Usually, the cloud computing involves providing dynamic and extensible virtualized resources via the Internet. The naissance of the cloud computing means that a computing capability can be regarded as a commodity for circulation through the Internet. The narrowly-defined cloud computing involves delivery and usage modes of IT infrastructures, which means to obtain desired resources on-demand and in an easily extensible way through the network. The generalized cloud computing involves delivery and usage modes of services, which means to obtain a desired service on-demand and in the easily extensible way through the network. The desired service may be associated with the IT, software and the Internet, or may be other services.
Usually, a cloud computing platform may be divided into three categories, i.e., a cloud platform of a storage type mainly used for data storage, a cloud platform of a computing type mainly used for data processing, and a comprehensive cloud computing platform used for data storage and data processing such as computing.